Help Getting files to work

[Kingjello]

So i installed the app on my phone, huawei p20 mate pro, and put on 5 games in both .iso and cso files. Now 3 off the games work, but the other 2 that are a iso and a cso file wont, when i try to open them it says its a invalid file. I have tested those two games on the pc version off ppsspp and there they do work, so my question is why wont they work on my phone when the app on my pc does reconize the 2 games